malformed filename %s: expected %s{version}_x{protocol-versi

Error message

malformed filename %s: expected %s{version}_x{protocol-version}_{os}_{arch} or %s{version}_{os}_{arch}

What it means

Remote getter error from Init: the checksum-file entry's filename doesn't match either accepted shape — {prefix}{version}_x{protocol}_{os}_{arch} (GitHub style) or {prefix}{version}_{os}_{arch} (releases.hashicorp.com style) — so its metadata cannot be parsed.

Source

Thrown at packer/plugin-getter/remote/getter.go:290

func (g *Getter) Init(req *plugingetter.Requirement, entry *plugingetter.ChecksumFileEntry) error {
	filename := entry.Filename
	res := strings.TrimPrefix(filename, req.FilenamePrefix())

	entry.Ext = filepath.Ext(res)
	res = strings.TrimSuffix(res, entry.Ext)

	parts := strings.Split(res, "_")
	switch {
	case len(parts) >= 4 && protocolVersionRe.MatchString(parts[1]):
		if !strings.HasPrefix(parts[0], "v") {
			return fmt.Errorf("malformed filename %s: version %q must have a v prefix alongside a protocol version", filename, parts[0])
		}
		entry.BinVersion, entry.ProtVersion, entry.Os, entry.Arch = parts[0], parts[1], parts[2], parts[3]
	case len(parts) == 3 && !strings.HasPrefix(parts[0], "v"):
		entry.BinVersion, entry.Os, entry.Arch = "v"+parts[0], parts[1], parts[2]
		entry.ProtVersion = ""
	default:
		return fmt.Errorf(
			"malformed filename %s: expected %s{version}_x{protocol-version}_{os}_{arch} or %s{version}_{os}_{arch}",
			filename, req.FilenamePrefix(), req.FilenamePrefix())
	}

	return nil
}

func (g *Getter) Validate(opt plugingetter.GetOptions, expectedVersion string, installOpts plugingetter.BinaryInstallationOptions, entry *plugingetter.ChecksumFileEntry) error {
	expectedBinVersion := "v" + expectedVersion
	if entry.BinVersion != expectedBinVersion {
		return fmt.Errorf("wrong version: %s does not match expected %s", entry.BinVersion, expectedBinVersion)
	}
	if entry.Os != installOpts.OS || entry.Arch != installOpts.ARCH {
		return fmt.Errorf("wrong system, expected %s_%s", installOpts.OS, installOpts.ARCH)
	}

	if entry.ProtVersion == "" {
		// The protocol version was resolved from the version's manifest.json

View on GitHub (pinned to eb36e3c3e4)

Solutions

Rename the release asset to follow the standard packer-plugin naming convention
Verify the checksum file references assets with the exact expected names

Defensive patterns

Strategy: validation

When it happens

Trigger: Thrown at packer/plugin-getter/remote/getter.go:290 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

AI-assisted analysis of hashicorp/packer@eb36e3c3e4 (2026-09-05). Data as JSON: /api/errors/5b90a8823b9a0be1. Report an issue: GitHub.